As for why breitbart.com is banned, one need look no further than this subthread. Posting from it is bomb-throwing whether you intend to or not, more or less regardless of the content. I suppose I should add that no, this is not because of political bias, it's because of anti-flamewar bias. There are sites with opposite politics which are banned for the same reason.
The source of this complaint is the James Damore lawsuit filing here (https://www.scribd.com/document/368692388/James-Damore-Lawsu...). You can find the portion mentioning Curtis Yarvin on page 37. That would be the best primary source to link to.
(Even the lawsuit description is problematic to me, as the "influential conservative personalities" mentioned -- Alex Jones, Theodore Beale, and Curtis Yarvin -- all come from the "alt-right" / conspiracy-oriented / "neo-reactionary" side of conservatism. There's no indication that this list also includes other influential conservative personalities like, say, George Will and Charles Krauthammer, so at first the description in the lawsuit seems overly broad. But the lawsuit text provides more context than Breitbart did, IMHO.)
* "isn't exactly allergic to the stuff" (re: white nationalism)
* wrote "Not all humans are born the same, of course, and the innate character and intelligence of some is more suited to mastery than slavery. For others, it is more suited to slavery. "
* asked "What's so bad about the Nazis?"
* etc
?
I'm not sure if it's liberals or conservatives who should be offended by that. Hopefully both.
It doesn’t make you uncomfortable to know that even if you’ve had no previous interactions with Google, you may be tracked and added to a list of undesirables? Who controls the list, who has power to add people to it, and what else are they doing with this list? What if they’re looking at his search history too? Would that be okay?
Danmore did not want to say set up a group of googlers into field sports (hunting Shooting and Fishing) did he.
[0] https://news.ycombinator.com/item?id=16103017
[1] https://news.ycombinator.com/from?site=breitbart.com
[2] https://news.ycombinator.com/item?id=16246184